# US 5,700,438 A · Process for removal of H2S from gas processing streams

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- Number: US 5,700,438 A
- Document ID: US5700438A
- Status: Granted
- Kind: A
- Application number: 08/695,156
- Filed: 1996-08-05
- Granted: 1997-12-23
- Earliest claimed: 1996-08-05
- Inventors: John C. Miller
- Web page: https://patentgrep.com/patent/US5700438A

## CPC

- B01D 53/48: Sulfur compounds
- B01D 53/52: Hydrogen sulfide
- B01D 2257/304: Hydrogen sulfide
- B01D 2257/306: Organic sulfur compounds, e.g. mercaptans
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)

## Abstract

A process for removing H2S and mercaptans from gas streams. The process comprises contacting such gas streams with an aqueous solution of copper complex of a water soluble amine to form water insoluble copper sulfide and regenerate free water soluble amine. The copper sulfide is removed from the system and recovered. Lastly, additional copper complex of the water soluble amine is formed by reacting the regenerated water soluble amine with a copper compound.

## Claims

### Claim 1

A process of removing H.sub.2 S and mercaptans from gas streams that may contain CO.sub.2 to an H.sub.2 S level below 0.1 ppm which comprises the steps:
a) contacting gas streams which contain H.sub.2 S and mercaptans with an aqueous solution of copper complex era sterically hindered, water soluble, primary amine which solution contains a molar excess of copper relative to content of sterically hindered, water soluble primary amine: to form water insoluble copper sulfide and regenerated free sterically hindered, water soluble, primary amine;
b) separating and recovering the copper sulfide; and then,
c) forming additional copper complex by reacting the regenerated sterically hindered, water soluble, primary amine with a copper compound.

### Claim 2 (depends on 1)

The process of claim 1 where the copper compound is a copper oxide.

### Claim 3 (depends on 2)

The process of claim 2 where the copper oxide is cupric oxide and steps a) through c) are repeated until substantially all the copper compound is exhausted.

### Claim 4 (depends on 2)

The process of claim 2 where the sterically hindered water soluble, primary amine is an alkanol amine.

### Claim 5 (depends on 4)

The process of claim 4 where the alkanol amine contains a terminal hydroxy alkyl group.

### Claim 6 (depends on 5)

The process of claim 5 where the alkanol amine is 2-amino-2-hydroxymethyl-1,3-propanediol.

### Claim 7 (depends on 1)

The process of claim 1 where the pH of the aqueous solution of the sterically hindered water soluble primary amine is within the range of between 5-11.

### Claim 8

A process for removing H.sub.2 S and mercaptans from gas streams that may contain CO.sub.2 to an H.sub.2 S level below 0.1 ppm which comprises the steps:
a) contacting gas streams which contain H.sub.2 S and mercaptans with an aqueous solution era copper complex era sterically hindered, water soluble, primary amine which solution contains slurried therein a molar excess of copper oxide relative to content of sterically hindered, water soluble primary amine to form insoluble copper sulfide and to regenerate free sterically hindered, water soluble, primary amine;
b) separating and recovering the copper sulfide; and then,
c) forming more copper complex of the regenerated sterically hindered, water soluble, primary amine by reacting it with copper oxide.

### Claim 9 (depends on 8)

The process of claim 8 where the sterically hindered, water soluble primary amine is an alkanol amine.

### Claim 10 (depends on 9)

The process of claim 9 where the water soluble, sterically hindered, alkanol amine contains a terminal hydroxy alkyl group.

### Claim 11 (depends on 10)

The process of claim 10 where the alkanol amine is 2-amino-2-hydroxymethyl-1,3-propanediol.

### Claim 12 (depends on 8)

The process of claim 8 where the copper oxide is cupric oxide.

### Claim 13 (depends on 8)

The process of claim 8 where steps a) through c) are repeated until substantially all the copper oxide is exhausted.

### Claim 14 (depends on 8)

The process of claim 8 where the pH of the aqueous solution of the sterically hindered water soluble primary amine is within the range of between 5-11.